Add button to Mac App to add sage executable to PATH

Imported from <a href="http://trac.sagemath.org/sage_trac/ticket/10556">trac #10556</a>.



Reported by: iandrus

Component: user interface

CC: 

Report Upstream: N/A

Authors: Ivan Andrus

Dependencies: <a href="http://trac.sagemath.org/sage_trac/ticket/11026">trac #11026</a>

Work issues: 

Reviewers: Karl-Dieter Crisman, John Palmieri

Merged in: sage-5.8.beta1

Attachments: <ol><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/10556/add-to-path.png">add-to-path.png: </a> by iandrus at 20110104T15:04:00</li><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/10556/trac_10556-extcode.patch">trac_10556-extcode.patch: </a> by iandrus at 20120713T09:38:59</li><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/10556/trac_10556-scripts.patch">trac_10556-scripts.patch: </a> by iandrus at 20120713T09:47:59</li></ol>